Latch



R. H. BLISS Jan. 12, 1943.

LATCH Filed April 10, 1940 Patented Jan. 12, 1943 i UNITED STATES PATENT OFFICE LATCH Robert H. Bliss, East Syracuse, N. Y.

Application April 10, 1940, Serial No. 328,954

6 Claims.

The present invention relates to window constructions and particularly to windows fabricated ofmetal and primarily designed and intended for use in the walls of, factories, shops, warehouses, public buildings, andother buildings within which there is the possibility of. an occasional explosion.

It has been appreciated for some time by those who are concerned with the management; of building structures in: which explosions are likely to occur that it: is: highly advantageous to. make use of window constructions of the: type whichineludes an outwardly opening sashwhich is so mounted for movement, and-is so retained" in its normally closed. position, that it will automatically open when subjected to an excessive. internal pressure, such as an excessive internal. air pressure. resulting. from an explosion, thus instantly relieving the pressure within. the structure and minimizing. the damage" resulting from the" explosion; While it is a. simple matter-to fabricate a: window construction having a sash. which will swing. outwardly when subjected to excessive internali pressure; it has proven to be more difii'cult to provide a satisfactory type of latching means which. normally maintains the: sash in. its closed position but whichnevertheless: automatically releases the sash to; permit the same" to automatically open under the: influence of excessive pressure iromwithin;

The present invention is primarily directed to the. provision of. a novel and: improved latching means which will effectively hold; the outwardly movable sash. in a normally closed position, or readilypermit manual-1 opening. and: closing of the sash as. desired, while; at the sametimeis always in instant. readiness to release the sash when an explosion. occurs while the sash is closed. The imDEQVfid: latching mean. has numerous novel features, for instance being adjustable soas to ofier more or less resistance to automatic sash opening, thus making it. possible for one and the same latching means: to be used: in association with. windows having: sashes of widely diiiering sizes; and which. therefore must be moved outwardly withv widely differing; forcesupon the occurrence of explosions of the same; intensity. Again, the improved latching; means is so designed that. it is particularly useful. when associated with a window having a sashwhich opens outwardly by swinging about a horizontal. axis passing throughv the; upper. end of, the sash, the upper horizontal sasl'r member being for instance mounted upon lateral. slides:- movable vertically in suitable guid'eways formed in the vertical side members of the frame, the lower horizontal sash member moving outwardly and upwardly in an are as the sash is opened and downwardly and inwardly in a similar are when it is closed.

The latching means when used with a window having a sash of this type is mounted upon the lower edge of the sash and is so designed that it will function not only as a latch to hold the sash in its normal or closed position but also as? a sash operating means, having a latch bolt which performs not only latching functions but which may also be manipulated manually; either directly or by means of a chain, to pry the lower edge of the sash away from the frame member against. which it normally is seated, thus initiating the-openingmovementof the sash. When the sash is of the type previously described, having its upper edge pivoted to members slidable vertically in the frame, it is also commonly connected to the frame by links, one on each side of the sash, each link being pivotally connected to the sash at a point adjacent the top of the sash and to the frame at a point adjacent the lower end of the sash opening. All that it is necessary to do to accomplish opening of the sash of a window of this type isto initiate movement of the lower sash member away from thesill of the frame, whereupon the links just described swing out of their normal vertical positions and the sash can be opened by a pullon a chain passing over a roller at the top of th sash. This type of sash is-well-known to those skilled in the art, many thousands being new in actual use. While not limited to use in conjunction with a sash of this type, the present invention in latching mech anism is particularly helpful when employed in this combination since, as has previously been pointed out, it performs not only latching functions, but likewise serves as a camming device when the sash is to be. manually opened, being efiective to place the sash; into such position that a downward pullon the top of the sash will be eiiective to complete its opening movement.

By way of example one embodiment of the invention isillustrated in the accompanying drawing. It will be apparent that the design and arrangement of the component elements ofthe invention may be modified in adapting the same to-windows of different types.

In the drawing:

Figure 1 is a verticaltransverse section through a metallic window construction, partly broken away, to whichthe novelsash latching means has been applied, the sash being shown in closed position;

which the latch bolt successively occupies when' the sash is being opened, either by the manual manipulation of the latch bolt or by the forcing outwardly of the sash due to pressure applied against it; and s Figure 6, a similar diagrammatic View, indicates the position of the latch bolt at the completionof its sash opening movement. V

The window construction which is illustrated in the drawing is of well-known type and need not be specifically described. The frame is generally indicated by the numeral Ill and the sash by the numeral I, the sash being shown in closed position in Figure 1 and in open position in Figure 2. Connected to the sash at the ends of the uppermost horizontal sash member l2 are rollers or friction blocks such as indicated at 13, which are free to move vertically in slots or guideways formed in the vertical side members of the frame as the window is moved to open or closed position. Sash supporting links are positioned on opposite sides of the sash, onesuch link being indicated at 14 and being pivotally connected at 15 tothe sash, adjacent the upper end "of the sash, and at I6 to the frame, adjacent the bottom of the sash opening and relatively close to the horizontal sill member l'i. When the sash is closed, the links M are vertically disposed as shown in Figure 1 and to effect opening of the sashit is necessary to move the lower edge of the sash outwardly a sufficient distance so that the pivot points 15 at the upper ends of the links 14 no longer lie in the vertical plane passing through pivots l6 and slides l3. Following this initial movement, Which may be brought about by pressure against the lower edge of the sash or by a pull on chain 34 passing over roller 35 and connected at 20, the sash can be opened as desired by a continued pull on the chain and will simultaneously swing in a clockwise direction (Figure 2) about its upper edge until it reaches some such position as shown in Figure 2.

The sash shown is adapted to be operated by a sash chain which is long enough to form a loop a convenient distance from the floor and which chain passes over the pulley 35 mounted on the upper sash member l2. Both ends of the sash chain may be fastened to the end of the latch bolt as shown or, alternatively, one end of the chain may be fastened to the latch bolt and the other end to the lower edge of the sash.

My improved latching and sash actuating means is generally indicated by the numeral and is shown to be affixed to the lower or free edge of the sash, the base or frame of the'latching means being rigidly attached to a bracket 22 which is in turn rigidly connected to and supported upon the lower sash member 23. Essentially the improved latching means comprises, in addition to the base 2|, the latch bolt 24 having aligned laterally projecting pivots 25 which project through opposed slots 26 formed in base 2|, the resilient spring 28 retained within a cylindrical recess 29 formed in the base 2], the spring abutments 39 and 3| and the adjusting screw 32 whereby the tension in the spring 28 may be increased or decreased as desired, the adjusting screw being provided with a lock nut 33.

The latch bolt is formed with a cam portion 36 upon which bears the lower spring abutment, so that the bolt will be spring retained either in its fully open or its fully closed position, and an arcuate edge 3'! which cooperates with the weathering angle member 21 or other appropriate catch. The exact position and height of the cam fportion is dependent on the strength of the spring 28 and the length of the elongated slots 26, 26

which are in turn dependent on the curvature of the opposite side of the latch bolt 31 which functions as a keeper. The relative position and height of the cam portion should be such that a sufficient snap action is assured to carry the sash to a securely closed position when the latch bolt and the lower spring abutment pass a dead center' relation in the closing movement. The curvature of the latch bolt should be gradual enough to allow the latch bolt to slide easily over the catch when the sash is being drawn to its closed position by the sash chain which is fastened to the end of the latch bolt as illustrated in Figure 4.

The lower ends of the elongated slots 26, 26 should be so located in the base that the curved portion of the latch bolt will extend below the catch and the slots should be extended up the base far enough to allow the pivots 25 to rise in the slots to a point at which the latch bolt can rotate to a vertical position while fulcruming about the point of contact between the notch 39 and the catch 21.

The nose 38 formed on the end of thelatch bolt should have its working surface in a horizontal plane when in "closed position and this horizontal surface should be extended to reach beyond the catch. This length is required to effect a point of fulcrum between the nose and the outside edge of the catch, which fulcrum is necessary to give a starting action when the latch is operated manually. The importance of these details will be realized from the following description of the mode of operation of the particular embodiment of the invention illustrated.

Referring to Figure 1 the latch isshown on a window of the type described in closed position.

The rounded bottom of the latch bolt which acts as a keeper extends below the top of catch 23 when the sash is closed and thus secures it When the sash is to be opened by means of the sash chain force is applied to the loop passing over the pulley and the latch bolt caused to rise in the elongated slots while rotating about the pivots 25 as shown in Figure 5. This movement continues until the latch bolt reaches the position in which it is shown in Figure 6. When the latch bolt reaches approximately the dotted line position of Figure 5, the nose of the latch bolt fulcrums against the outside edge of the catch and gives the sash a' start which facilitates the opening movement.

The upward movement of the latch bolt in the elongated slots is resisted by the spring until the cam portion of the bolt and the lower spring abutment pass beyond a dead center relation. From this point, and during the time when the starter action is occurring, the spring aids the movement of the latch bolt. The chain is pulled until the sash has been set into a desired position as shown in Figure: 2, it beingthen held in position by the pivoted friction shoes l3. The sash is closed by pulling the inside chain. When both endsof the sash chain are fastened to the latch bolt, this action brings the bolt-into alignment with the top of the catch over which the chain is being. pulled asshown indotted lines in Figure 4. When the arcuate bottom of the latch bolt reaches the top of the catch and starts to rise. over it, the pivots start to ride upin the elongated slots. This continues untilthe bolt reaches the position in which it isshown in full lines in Figure 4 and, after passing beyondthis position in the closing direction, the spring forces the sash the remaining distance and securely holds it in closedposition as shown in Figure 1. When the end of the sash chain which is used to pull the sash closed is fastened to the lower sash member, the closing movement of the latch bolt is illustrated by Figures 6- and 5. As the sash swings in the closing direction, the nose 38 of the latch bolt strikes the top of the catch as shown in Figure 6. The force ofstriking causes the latch bolt to move successively through the positions shown in Figure in the closing direction and finally rest in the position shown in Figure 1.

When the sash is subjected to a high uniform pressure the resulting force between the notch 39 and the catch 2'! is exerted on the latch bolt substantially below the pivots and causes the latch bolt to move successively through the positions shown in Figures 5 and 6, during which movement the latch bolt passes a dead center relation with the lower spring abutment and snaps to its open position. The compression in the spring determines the resistance offered to bodily movement of the latch bolt and may be varied by the adjusting screw 32 and the latch thereby made to respond automatically to different pressures.

Various changes and modifications may be made in the device described and illustrated without departing from the scope of the invention as defined in the following claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A latch for a window which includes a frame member and a sash member mounted for swinging movement relatively to said frame member about a horizontal axis adjacent the upper edge of the sash member, said latch comprising a latch boit having a keeper portion with a curved edge adapted to slidably engage a stationary frame part and an end portion adapted to positively engage such frame part, and means mounting said latch bolt on the sash, adjacent the lower edge thereof, for rocking movement about an axis and for bodily movement in a piane disposed at an angle to said axis, whereby the sash may be pulled to closed position by an operating force applied to the latch bolt at a point spaced from the axis about which the latch bolt may rock, the latch bolt being bodily shifted during the final closing movement of the sash as the keeper portion thereof rides over the stationary frame part and thereafter moving to sash retaining position, or the sash may be moved to closed position by forces otherwise applied, the latch bolt pivoting into sash retaining position during the final closure movement of the sash upon contact of the said end portion thereof with said stationary frame part, the latch bolt being also adapted to rotate about its axis to permit the keeper portion thereof to disengage said stationary frame. part to permit the sash. to swing to open position. when a greater than perd'etermined pressure is applied directly to the sash in asashopening direction- 2. A- latch for awindow which includes a frame member and a sash member mounted for swinging. movementrelatively to'said frame member about a horizontal axis adjacent the upper edge of the sash member, said latch comprising a latch bolt having a keeper portion with a curved edge adapted toslidably engage a stationary frame part and an end portion adapted to positively engage. such frame part, and means mounting said latch bolt on the sash, adjacent the lower edge thereof, for rocking movement about an axis and for bodily movement in a pl'ane disposed at anangle to said axis, whereby the sash may be pulled to closed position by an operating force applied to the latch bolt at a point spaced from the axis about which the latch bolt may rock, the latch bolt being bodily shifted during the final closing movement of the sash as the keeper portion thereof rides over the stationary frame part and thereafter moving to sash retaining position, or the sash may be moved. to closed position by forces otherwise applied, the latch bolt pivoting into sash rettaining position during the final closure movement of the sash upon contact of the said end portion thereof with said stationary frame part, the latch bolt being also adapted to rotate about its axis to permit the keeper portion thereof to disengage said stationary frame part to permit the sash to swing to open position when a greater than predetermined pressure is applied directly to the sash in a sash opening direction, said means including a resilient element normally urging the latch bolt bodily away from the upper edge of the sash.

3. A latch for a window which includes a frame member and a sash member mounted for swinging movement relatively to said frame member about a horizontal axis adjacent the upper edge of the sash member, said latch comprising a latch bolt having a keeper portion with a curved edge adapted to slidably engage a stationary frame part and an end portion adapted to positively engage such frame part, and means mounting said latch bolt on the sash, adjacent the lower edge thereof, for rocking movement about an axis and for bodily movement in a plane disposed at an angle to said axis, whereby the sash may be pulled to closed position by an operating force applied to the latch bolt at a point spaced from the axis about which the latch bolt may rock, the latch bolt being bodily shifted during the final closing movement of the sash as the keeper portion thereof rides over the stationary frame part and thereafter moving to sash retaining position, or the sash may be moved to closed position by forces otherwise applied, the latch bolt pivoting into sash retaining position during the final closure movement of the sash upon contact of the said end portion thereof with said stationary frame part, the latch bolt being also adapted to rotate about its axis to permit the keeper portion thereof to disengage said stationary frame part to permit the sash to swing to open position when a greater than predetermined pressure is applied directly to the sash in a sash opening direction, said means including a resilient element normally urging the latch bolt bodily away from the upper edge of the sash, and an adjustable abutment for said element whereby the action of said element may be modified.

4. A latch for a window which includes a frame member and a sash member mounted for swinging movement relatively to said frame member about a horizontal axis adjacent the upper edge of the sash member, said latch comprising a latch bolt having a keeper portion with a curved edge adapted to slidably engage a stationary frame part and an end portion adapted to positively engage such frame part, and means mounting said latch bolt on the sash, adjacent the lower edge thereof, for rocking movement about an axis and for bodily movement in a plane disposed at an angle to said axis, whereby the sash may be pulled to closed position by an operating force applied to the latch bolt at a point spaced from the axis about which the latch bolt may rock, the latch bolt being bodily shifted during the final closing movement of the sash as the keeper portion thereof rides over the stationary frame part and thereafter moving to sash retaining position, or the sash may be moved to closed position by forces otherwise applied, the latch bolt pivoting into sash retaining position during the final closure movement of the sash upon contact of the said end portion thereof with said stationary frame part, the latch bolt being also adapted to rotate about its axis to permit the keeper portion thereof to disengage said stationary frame applied directly to the sash in a sash opening direction, said means including a helical spring disposed in a plane substantially parallel to the plane of the sash, an abutment slidably engaging the latch bolt, and an adjustable abutment, the ends of said spring engaging said abutments, respectively;

5. The combination set forth in claim 4 in which that portion of the latch bolt which is slidably engaged by one spring abutment is shaped as a cam, the spring also acting through this cam shaped portion to tend to maintain the latch bolt in either sash latching position or in inoperative position.

6. The combination set forth in claim 1 in which a flexible tension element is attached to that end of the latch bolt which is remote from the frame engaging end portion thereof, said tension element being adapted to be utilized in applying a pull to the latch bolt to effect closing of the sash.

ROBERT H. BLISS. 

